TURBlNIDiE. 307 



TuRBONiTELLA, cle Koninck, 1881. 



Distr. — Devon, to Carb. ; Europe. T. biserialis, de Kon. 



Shell turbiiiiform, with convex, smooth or nodulous whorls ; 

 mouth round or oval, inner lip callously thickened, outer lip 

 sharp, thin ; a narrow umbilical slit. 



Rhabdopleura, de Koninck. 



Distr. — Monodonta solida, Kon. Carb, 



Conical, height and diameter about equal; whorls 4-5, slightl}^ 

 convex, rapidly enlarging, the last more than half the total 

 length, striate, and finely spirally ribbed ; aperture transversely 

 rounded ; inner lip somewhat callous, curved and thickened below. 



Onkospira, Zittel. 



Distr. — 0. ranellatus^ Quenst. Coral Rag. 



Shell thin, lengthened-trochiform, spire pointed ; whorls con- 

 vex, spirally ribbed, keeled or clathrate with one or two varices, 

 which are continuous, as in Ranella ; mouth rounded-ovate ; 

 columella forming an angle with the thickened outer lip. 



Hamusina, Gemmellaro. 

 Distr. — Lias ; Europe. H. Bertheloti, d'Orb. 

 Shell thin, conical-turreted, sinistral, tuberculate, imperforate ; 

 spire sharp; body-whorl angular; aperture rounded, inner lip 

 callous. 



Platyacra, v. Ammon, 1882. 

 Distr. — Rhtetian ; Bavaria. P. impressa, Schaf h. 

 Shell thin, turreted, sinistral, widely and deeply umbilicate ; 

 whorls with a nodulous keel ; apex flattened. 



Imperator, Montfort. 



Syn. — Astralium, Link. Tubicanthus, Swn. Canthorbis, Swn. 

 Hercoles, Montf. 



Distr. — 50 sp. East and West Lidies, W. America, Australia. 

 Fossil. Trias — . 



Shell trochiform, depressed conic ; whorls rugose or spinous, 

 the latter especially at the sharply angulated periphery of the 

 last whorl ; aperture subquadrangular, subtruncated in front. 

 Operculum calcareous. 



IMPERATOR (restricted). Umbilicated. Operculum with a 

 subcentral tubercle and a spiral submarginal rib. /. longispina, 

 Lam. (Ixxx, 23, 24). 



CALCAR, Mont. (Stella, Klein. Cyclocantha, Swains. Astrea, 

 Bolt. Turboidea, Seeley.) Not umbilicated ; spire more ele- 

 vated. Operculum externally subspiral, and with a central pit. 

 W. Indies, Indian Ocean. /. sfellaris, Gmel. (Ixxx, 25). 



GUILFORDIA, Gray. Periphery with long spines ; whorls granose, 



